To develop a software system to assist radiotherapists in investigational protocols as well as standard treatment management by facilitating information access/retrieval, organizing data handling/processing and providing expert advice. Specific objectives include: 1. Establishment of requirements for a Radiation Oncology Data information and Advisory System (RODlAS) to meet expressed needs/concerns of cooperating radiotherapists and clinical trial investigators for enhanced effective protocol management. 2. Translation of the requirements identified into an expert system design concept, including provisions for exploiting existing data base systems, such as the National Cancer Institute's Physician Data Query (PDQ) system. 3. Exploration and feasibility assessment of the various practical issues that would be involved in implement the concept. 4. Development and demonstration of a prototype expert system applied to a limited problem domain to provide a concrete example of the system's utility and how it might operate.